Mont St Michel has become an island for the first time since 1879 after a high tide briefly disconnected it from mainland France.

Hundreds of people gathered to watch the event on Wednesday evening, which only lasted about 20 minutes, as the English Channel entirely surrounded the Unesco world heritage site.

"For the first time in a long time we will see the sea surround the Mont," Laurent Beauvais, president of the Basse-Normandie region, told Le Figaro.

"It's rare and we're here," an unnamed couple told Le Parisienne. "We came at the right time."

The island in Normandy is famous for its abbey, which dates to the 11th century, and its historical strategic importance. The site attracts around three million tourists a year.

Until recently the island was connected to the mainland by a tidal causeway. However, a renovation project that began in September last year means that the causeway is being dismantled and will eventually be replaced by a bridge. Silt levels around the causeway have also been reduced.